Releasable swivel chair support construction

ABSTRACT

A SWIVEL CHAIR SUPPORT CONSTRUCTION EMPLOYS A SPINDLE WITH ONE END ADAPTED TO BE ATTACHED TO A CHAIR SEAT AND A PORTION OF THE SPINDLE BEING THREADED FOR A SUFFICIENT DISTANCE TO PROVIDE VERTICAL ADJUSTABILITY OVER THE POSITION OF THE CHAIR TO THE DESIRED EXTENT, A TUBULAR MEMBER RECEIVING THE SPONDLE IN LOOSE SLIDING ENGAGEMENT AND ADAPTED TO BE SECURED TO A CHAIR BASE AND INCLUDING A LOAD BEARING ELEMENT, A LOAD SUPPORTING NUT THREADEDLY ENGAGED ON THE SPONDLE, AND MEANS FOR RELEASABLY CONNECTING TOGETHER THE SPINDLE AND TUBULAR MEMBER TO PREVENT AXIAL SEPARATION THEREOF WHEN THE CHAIR IS LIFTED. THE MEANS INCLUDES A HOOK HAVING AN ARCUATE PORTION EXTENDING AROUND AT LEAST A MAJOR PORTION OF THE PERIPHERY OF THE SPINDLE ADJACENT THE TUBULAR MEMBER AND AN ARM FIXED TO AND   EXTENDING FROM THE HOOK TOWARD THE TUBULAR MEMBER AND TERMINATING IN A FREE END WHICH IS ARRAGED TO BE FREE FROM ENGAGEMENT WITH THE TUBULAR MEMBER WHEN THE HOOK IS COCKED IN ONE DIRECTION ON THE SPINDLE TO DISPLACE THE FREE END OF THE ARM AWAY FROM THE SPINDLE AND TO ENGAGE A PORTION OF THE TUBULAR MEMBER TO PREVENT SEPARATION OF THE HOOK FROM THE TUBULAR MEMBER WHEN THE HOOK IS COCKED IN THE OPPOSITE DIRECTION ON THE SPINDLE.

P 20, 1971 R. w. PRESCOTT 3,506,234

RELEASABLE SWIVEL CHAIR SUPPORT CONSTRUCTION Filed Feb. 24. 1970 2Sheets-Sheet 1 32 3o 36 RI 26 e I 33 34 1 2 i 56{-(( .w j la p 20, 1971R. w. PRESCOTT RELEASABLE SWIVEL CHAIR SUPPORT CONSTRUCTION Filed Feb.24. 1970 2 Sheets-Sheet 2 FIG 5 FIG 6 United States Patent 3,606,234RELEASABLE SWIVEL CHAIR SUPPORT CONSTRUCTION Robert W. Prescott,Lunenburg, Mass., assignor to Collier-Keyworth Company, Gardner, Mass.Filed Feb. 24, 1970, Ser. No. 13,534 Int. Cl. F16m 13/00 U.S. Cl.248-406 7 Claims ABSTRACT OF THE DISCLOSURE A swivel chair supportconstruction employs a spindle with one end adapted to be attached to achair seat and a portion of the spindle being threaded for a sufiicientdistance to provide vertical adjustability over the position of thechair to the desired extent, a tubular member receiving the spindle inloose sliding engagement and adapted to be secured to a chair base andincluding a load hearing element, a load supporting nut threadedlyengaged on the spindle, and means for releasably connecting together thespindle and tubular member to prevent axial separation thereof when thechair is lifted. The means includes a hook having an arcuate portionextending around at least a major portion of the periphery of thespindle adjacent the tubular member and an arm fixed to and extendingfrom the hook toward the tubular member and terminating in a free endwhich is arranged to be free from engagement with the tubular memberwhen the hook is cocked in one direction on the spindle to displace thefree end of the arm away from the spindle and to engage a portion of thetubular member to prevent separation of the hook from the tubular memberwhen the hook is cocked in the opposite direction on the spindle.

This invention relates to a swivel chair support construction of thethreaded spindle type in which a seat height adjustment handwheel, orbell, is used, and more particularly to a novel and improvedconstruction for connecting the spindle to the base or leg assembly ofthe chair.

Typically, such swivel chair support constructions employ a fittingsecured to the upper end of the spindle and arranged to be attached to avariety of chair seats. Preferably, the spindle has an unthreaded lowerportion to provide a smooth cylindrical bearing surface arranged tocooperate with a smooth tubular recess in the leg assembly to minimizewear of the spindle and recess while supporting the chair, and athreaded upper portion on which the bell is threaded for use inadjusting the height of the chair.

In practice, the spindle and its upper end fitting, with or without abell mounted in place, is permanently secured to the chair seat. Thissub-assembly is then adapted to be mounted on any of a wide variety ofleg assemblies, depending upon the style and color desired. In someconstructions the bell must be threaded on the spindle before the latteris secured to the chair seat, while in others, as shown for example inU.S. Pat. No. 3,161,396 the bell may be placed or may be interchangedwith another bell after the spindle is secured to the chair seat.

In either event, the sub-assembly of chair seat and spindle must then beadapted to be releasably and interchangeably mounted on a variety of legassemblies to provide the desired choice of style and colorcombinations. After the chair is completely assembled, the spindle andchair seat must be so connected to the leg assembly that the entirechair can readily be lifted and moved from place to place simply bygrasping the chair seat, without affecting the height adjustment orseparating the chair from the leg assembly. One commonly employed meansof accomplishing this is to provide a set screw in the bell in positionto engage beneath a flange or collar at the top of the leg assembly, butthis is unsightly and difficult to actuate, usually requiring the use ofa tool such as a wrench or screwdriver.

One object of the invention is to provide a swivel chair supportconstruction of the type described embodying a self-locking featurewhich automatically locks the chair seat at the desired height, while atthe same time permitting the height of the chair to be readily adjustedby rotation of the bell when the chair is empty.

Another object of the invention is to provide a connecting means whichpermits the entire chair to be lifted and moved from place to placewithout change of the height adjustment or separation of leg assemblyfrom the chair seat simply by grasping the chair seat, which is readilyreleasable without the use of tools, and which prevents significantaxial movement of the nut along the spindle when the chair seat isrotated.

Other objects and advantages will become apparent from the followingdescription of a preferred embodiment of the invention, taken togetherwith the attached drawings thereof, in which:

FIG. 1 is a view in side elevation, partly broken away and incross-section, of a swivel chair support construction in accordance withthe invention;

FIG. 2 is a view in section taken along line 22 of FIG. 1 of theconnecting means and spindle of the construction;

FIG. 3 is a view of the connecting means or hook in cross-section takenalong line 33 of FIG. 2;

FIG. 4 is an exploded perspective view of a portion of the constructionshown in FIG. 1;

FIG. 5 is a view in side elevation partly broken away, of a portion ofthe support construction of FIG. 1 as the spindle is inserted into orremoved from the tubular member of the leg assembly;

FIG. 6 is a view similar to that of FIG. 5, showing actuation of theconnecting means to permit engagement or disengagement; and

FIG. 7 is a view similar to that of FIGS. 5 and 6 showing the connectingmeans in engaged position to prevent separation of the spindle from thetubular member of the leg assembly.

Referring to FIG. 1, the construction has a threaded spindle 10 having asmooth cylindrical bearing surface 12. The upper end of spindle 10 issecured in any suitable manner, preferably by non-detachable staking, toa conventional fitting 14 which is arranged to be secured to the bottomof a chair seat and which may provide for tilting of the chair seat ifdesired. Leg assembly 16 is provided with a bearing for supporting thespindle. The bearing includes a washer 18 rigidly fastened to and seatedon top of leg assembly 16 and a flanged steel support collar 20 which isrigidly fastened to washer 18 and held in place by a swaged steel tube22. Mounted within tube 22 is a bearing liner 24 of synthetic plasticcompositions supported on collar 20 by means of radially extendingflange 26 which is formed integrally with liner 24 and which serves as aload bearing element. The outer periphery of flange 26 is located at adistance R (FIG. 1) from the axis 28 of rotation of spindle 10. While avariety of materials such as synthetic plastic compositions are suitablefor use in making the bearing liner, as is well known, the materialpreferred for best results is a superpolyamide. While the length oflower unthreaded portion 12 of spindle 10 is not critical, it ispreferred that it be at least half the length of bearing liner 24.

A load supporting nut 30 is engaged with the threads on spindle 10 andhas an annular recess 32 near the top thereof.

. Bell 34 may be ofany conventional size or shape to match the legassembly 16 and has a center opening in the top thereof arranged to beswedged in place in recess 32 around nut 30 in fixed engagementtherewith.

Connecting means in the form of an embossed hook 36 is arranged to bemounted around spindle 10 between nut 30 and flange 26 and hassubstantially flat arcuate portion 38 resting on flange 26 and an arm 40which extends radially outwardly from portion 38 beyond the outerperiphery of flange 26 and then downwardly and radially inwardly belowcollar 20 and defines an annulus about a portion of the outer peripheryof flange 26 and collar 20.

Referring to FIGS. 2 and 3, hook 36 has a key 50, opposite hook arm 40extending radially inward from portion 38, with flared end portion 52,and arranged to be engaged in a cooperating and vertically extendingkeyway 54 and terminating below the threads on spindle 10 cut in spindle10 at concave bottom end portion 55, and has four detents 56 pressed inportion 38, spaced 90 apart and extending 0.03" above the otherwise flatsurface 58 of portion 38. Detents 56 are arranged to seat in recesses 60in the bottom 62 of nut 30 to restrain rotation of the nut 30 on spindle10. The distance from the central axis 66 of opening 68 (FIG. 3) inportion 38 to inner surface 64 of arm 40 varies from R which is lessthan R at the bottom or free edge 70 of arm 40, to R which is greaterthan R near the point 72 at which arm 40 begins to extend downwardly.Opening 68 through hook 36 has a radius R.;, greater than the outerthread radius R (FIG. 1) of spindle 10, but less than R to permitportion 38 to be tilted from a horizontal plane (FIGS. 6 through 8).

Chair seat with attached spindle 10 is assembled with leg assembly 16 inthe following fashion:

Hook 36 is mounted on spindle 10 beneath nut 30 with key 50 aligned withkeyway 54. Spindle 10 is then inserted in tubular member 22 of legassembly 16 until the free end 70 of arm 40 rests on flange 26 withportion 38 either in a horizontal plane or rotated clockwise from thehorizontal (as shown in FIG. 5). Hook 36 is then tilted to raise arm 40automatically by the urging of flange 26 against edge 70 as spindle 10is inserted further into tubular member 24 until free end 70 of arm 40projects radially beyond flange 26. As shown in FIG. 6, the tilting ofhook 36 may also be performed manually, if desired. Spindle 10 is thanfully inserted into member 24 until nut 30 rests on hook 36. Ann 40first passes around flange 26 and collar and as the apparatus approachesthe position shown in FIG. 1, flange 26 and bottom 62 of nut 30cooperate to align hook 36 with portion 38 in a horizontal plane andwith arm 40 projecting around and below collar 20 and flange 26 as shownin FIG. 1. Bell 34 together with nut 30, are then rotated until the seatis at the desired height, the detents 56 simply riding into and out ofengagement with recesses 60 during this operation. Bell 34 shrouds hook36 and the outer surface thereof presents a smooth appearance to theeye.

The detents 56 on hook 36 and indents in bottom 62 of nut 30 cooperateto prevent, absent adjustment, seat height from changing over anextended period of use of the chair since they, together with key tendto prevent rotation of the nut 30 with respect to spindle 10 and causerelative rotation to occur between the bottom of hook 36 and the flange26 of bearing liner 24 when the chair seat is rotated on the legassembly.

After the chair has been assembled, hook 36 prevents spindle 10 frombeing removed or axially separated accidentally, for example, as aresult of lifting the chair by its seat, from tubular member 22.

If chair seat with attached spindle 10 is lifted relative to tubularmember 22, key 50 is lifted at flared end 52 by keyway 54, tilting thehook 36 so that arm 40 engages a portion of collar 20, as shown in FIG.7, and the opposite edge portion of hook 36 engages between threads ofthe spindle. In this cocked position hook 36 prevents separation ofspindle 10 from the leg assembly.

If key 50 slips in keyway 54 and hook 36 is not tilted sufiiciently tobecome cocked against spindle 10, flared end 52 comes into contact withbottom end 55 of key- Way 54 and hook 36 and arm 40 are urged thereby ina direction perpendicular to axis 28 toward keyway 54. Portion 38becomes wedged on top of collar 20 with inner surface 64 of arm 40pulled against flange 26 and tilting of edge 70 of arm 40 about flange26 is prevented until the chair is lowered.

However, removal of spindle 10 from tubular member 22, for example inorder to assemble the chair with a new leg assembly, is quickly andsimply accomplished. Hook 36 is pushed, in the direction of arm 40,against spindle 10, hook 36 and arm 40 are tilted to the position shownin FIG. 6 with arm 40 clear of collar 20 and flange 26, and spindle 10is withdrawn from tubular member 22. This operation is performed mosteasily by placing the chair on its side and backing off bell 34 and nut30 to expose the hook 36.

Thus, the invention prevents accidental removal of the seat from the legassembly or accidental change of the height adjustment and permitsextremely fast assembly and disassembly, without the use of tools, ofdifferent seats and leg assemblies. Furthermore, it permits the use of ahell with a smooth surface, rather than a bell having a set screwtherein and, therefore, improves the overall appearance of the chair,while eliminating the risk of personal injury or of marring of thesurface of the bell caused by slipping of a screwdriver used to adjustthe set screw.

What is claimed is:

1. A swivel chair support construction comprising a spindle having oneend adapted to be attached to a chair seat, a portion of said spindlebeing threaded for a sufficient distance to provide verticaladjustability of position of the chair to the desired extent,

a tubular member receiving said spindle in loose sliding engagement,said tubular member being adapted to be secured to a chair base andincluding a load bearing element and a flange, a load supporting nutthreadedly engaged on said spindle,

means for releasably connecting together said spindle and tubular memberto prevent axial separation thereof when the chair is lifted, said meanscomprising a hook having an arcuate portion extending around at least amajor portion of the periphery of said spindle adjacent the tubularmember and being a loose fit on the spindle and freely slidable alongthe axis of the spindle independently of the not when the arcuateportion lies in a plane perpendicular to said axis but binding upon thespindle when the hook is cocked on the spindle,

and an arm fixed to and extending from said hook toward the tubularmember and terminating in a free end, said arm being free fromengagement with the tubular member when the hook is cocked in .onedirection on the spindle to displace the free end of the arm away fromthe spindle, and being arranged to engage a flange of the tubular memberto prevent separation of the hook from the tubular member when the hookis cocked in the opposite direction on the spindle.

2. The swivel chair support construction as claimed in claim 1 whereinsaid spindle has an unthreaded portion and said tubular member has anend adapted to receive said unthreaded portion in loose slidingengagement and a bearin g is disposed at said end, said hook beingdisposed between said load supporting nut and said bearing.

3. The swivel chair support construction as claimed in. claim 1 whereinsaid arcuate portion of said hook defines an annulus, said annulus beingdisposed around the periphery of said spindle. j

4. A swivel chair support construction as claimed in claim 1 whereinsaid nut carries a bell shrouding said hook and said bearing.

5. The swivel chair support construction as claimed in claim 1 whereinone of said hook and said nut has a detent and the other of said hookand said nut has an indent said detent being arranged to mate with saidindent when said spindle and said key rotate relative to said nut in themanner that said nut is prevented from rotating further relative to saidspindle.

6. The swivel chair support construction as claimed in claim 1 whereinsaid spindle has a keyway disposed parallel to said axis of said;spindle and said hook has'a key, said key being arranged to be engagedin said keyway for rotation of said hook; about said axis of saidspindle when said spindle rotates about said axis.

7. A swivel chair support construction as claimed in claim 6 whereinsaid keyway terminates in a bottom end portion along said spindle andsaid key is disposed remote from said arm on said arcuate portion,

said key and said bottom end portion being arranged to cooperate to urgesaid arm to engage said tubular member when said chair is lifted andsaid hook is other than cocked on said spindle.

References Cited UNITED STATES PATENTS 1,513,695 10/1924 Dawson 248-4062,359,966 10/ 1944 Bolens 248-406 2,999,665 9/1961 Ericson et al.248-405 WILLIAM H. SCHULTZ, Primary Examiner US. Cl. X.R. 248-188]

